The Transition From Turbulent to Laminar Gas Flow in a Heated Pipe

Abstract

Experimental results are reported on the heat transfer and fluid friction of heated hydrogen and helium gas flows undergoing transition from turbulent to laminar flow in a circular tube. The entering Reynolds numbers range from 2350 to 12,500 and the nondimensional heat-flux parameter ranges from 0.0021 to 0.0061. Local heat-transfer coefficients and friction factors are obtained, and the flow transition, which is evident in these results, is verified at small heat fluxes by measuring directly the turbulence intensity at the center line with a hot-wire anemometer. At large heat fluxes, laminarization is found to occur at local bulk Reynolds numbers well in excess of the minimum number for fully turbulent adiabatic flow, and the resulting heat-transfer coefficients are much lower than those associated with fully turbulent flow at the same Reynolds number. The relation between laminarization in heated tubes and in severely accelerated external boundary layers is investigated and some similarities are noted. The acceleration and pressure-gradient parameters used to predict boundary-layer laminarization are modified for tube flow and used to correlate the initiation and completion of laminarization in the heated tube.

Thermal‐Fluid Transport Phenomena of aStrongly‐Heated Gas Flow in Parallel Tube Rotation

“…This phenomenon is referred to as laminarization. The experimental and numerical studies on the thermal fluid transport phenomena have been performed by several investigators: Bankston (1970), Coon and Perkins (1970), McEligot et al (1970), Perkins et al (1973), Mori and Watanabe (1979), Ogawa et al (1982), Kawamura (1979). Torii et al (1993) and Torii and Yang (1997a) investigated the transport phenomena in the strongly heated circular tube flows by means of a Reynolds stress turbulence model and a two-equation heat transfer model, respectively.…”

Initial Scaling Studies and Conceptual Thermal Fluids Experiments for the Prismatic NGNP Point Design

“…One may hypothesize that for a turbulent flow, the acceleration would tend to stabilize bursting from the important viscous layer and thereby reduce turbulent transport [Corino and Brodkey, 1969]. With sufficiently large acceleration, a condition called "laminarization" can occur where flows expected to be turbulent show heat transfer parameters as low as in laminar flows [Bankston, 1970]. A measure of this phenomenon is an acceleration parameter K v defined as ( b /V b 2 ) (dV b /dx) [McEligot, Coon and Perkins, 1970].…”

Experimental Investigation of Convection Heat Transfer in High Pressure and High Temperature Gas Flows

“…The criteria for the occurrence of DTHT, flow laminarization, and the heat transfer characteristics of these phenomena have been the subject of previous studies by several investigators [15][16][17][18][19][20]. Shome [7] defined flow laminarization as the state in which the ratio of Reynolds shear stress to the viscous wall shear stress attenuates to 5% of the constant property value for the same value of the inlet Reynolds number.…”